AudioCodes Mediant 4000 SBC User Manual page 222

Note:
•
The device can send recordings (media) to up to three active SRSs. In other
words, any one of the following configurations are supported:
√
Up to three standalone (active) SRSs.
√
Up to three active-standby SRS pairs (i.e., six SRSs, but recordings are sent
only to the three active SRSs).
√
One standalone (active) SRS and two active-standby SRS pairs.
√
Two standalone (active) SRSs and one active-standby SRS pair.
•
SRS active-standby redundancy is a license-dependent feature and is available
only if it is included in the License Key installed on the device. Therefore, the
SIPRec feature can require two licenses – the regular license ("SIPREC") for
standalone (active) SRSs and a license ("SIPRECRED") for SRS active-standby
redundancy. If you are implementing only standalone SRSs, you only need the
"SIPREC" license. If you are implementing SRS active-standby redundancy, you
need both licenses.
•
The "SIPREC" license defines the maximum number of sessions for active SRSs
(standalone SRS and the active SRS in the active-standby redundancy pair). The
"SIPRECRED" license defines the maximum number of SIPRec sessions for the
standby SRS in the active-standby redundancy pair. For example, if you want to
support 10 SIPRec sessions per SRS, the required licenses for various scenarios
are as follows:
√
One standalone SRS: SIPREC = 10
√
Two standalone SRSs: SIPREC = 20
√
One active-standby redundancy pair: SIPREC = 10; SIPRECRED = 10
√
Two active-standby redundancy pairs: SIPREC = 20; SIPRECRED = 20
√
One standalone SRS and two active-standby redundancy pairs: SIPREC = 30;
SIPRECRED = 20
The device initiates a recording session by sending an INVITE message to the SRS when
the recorded call is connected. The SIP From header contains the identity of the SRC and
the To header contains the identity of the SRS. The SDP in the INVITE contains:

Two 'm=' lines that represent the two RTP/SRTP streams (Rx and Tx).

Two 'a=label:' lines that identify the streams.

XML body (also referred to as metadata) that provides information on the participants
of the call session:
•
<group id>: Logging Session ID (displayed as [SID:nnnnn] in Syslog), converted
from decimal to hex. This number remains the same even if the call is forwarded
or transferred. This is important for recorded calls.
•
<session id>: Originally recorded Call-ID, converted from decimal to hex.
•
<group-ref>: same as <group id>.
•
<participant id>: SIP From / To user.
•
<nameID aor>: From/To user@host.
•
<send> and <recv>: ID's for the RTP/SRTP streams in hex - bits 0-31 are the
same as group, bits 32-47 are the RTP port.
•
<stream id>: Same as <send> for each participant.
•
<label>: 1 and 2 (same as in the SDP's 'a=label:' line).
User's Manual 222
Mediant 4000 SBC
Document #: LTRT-40203